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                [Usaco2008 Mar]牛跑步                </h1>
                <p>时间限制：10s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：162MB</p>			</div>
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                                <h3>题目描述</h3><p><p><span style="font-size: medium">BESSIE准备用从牛棚跑到池塘的方法来锻炼. 但是因为她懒,她只准备沿着下坡的路跑到池塘, 然后走回牛棚. BESSIE也不想跑得太远,所以她想走最短的路经. 农场上一共有M (1 &lt;= M &lt;= 10,000)条路, 每条路连接两个用1..N(1 &lt;= N &lt;= 1000)标号的地点. 更方便的是,如果X&gt;Y,则地点X的高度大于地点Y的高度. 地点N是BESSIE的牛棚;地点1是池塘. 很快, BESSIE厌倦了一直走同一条路.所以她想走不同的路,更明确地讲,她想找出K (1 &lt;= K &lt;= 100)条不同的路经.为了避免过度劳累,她想使这K条路经为最短的K条路经. 请帮助BESSIE找出这K条最短路经的长度.你的程序需要读入农场的地图, 一些从X_i到Y_i 的路经和它们的长度(X_i, Y_i, D_i). 所有(X_i, Y_i, D_i)满足(1 &lt;= Y_i &lt; X_i; Y_i &lt; X_i &lt;= N, 1 &lt;= D_i &lt;= 1,000,000). </span></p></p><hr/><h3>输入格式</h3><p><p><span style="font-size: medium">* 第1行: 3个数: N, M, 和K </span></p>
<p><span style="font-size: medium">* 第 2..M+1行: 第 i+1 行包含3个数 X_i, Y_i, 和 D_i, 表示一条下坡的路. </span></p></p><hr/><h3>输出格式</h3><p><p><span style="font-size: medium">* 第1..K行: 第i行包含第i最短路经的长度,或-1如果这样的路经不存在.如果多条路经有同样的长度,请注意将这些长度逐一列出. </span></p></p><hr/><h3>样例输入</h3><pre>5 8 7
5 4 1
5 3 1
5 2 1
5 1 1
4 3 4
3 1 1
3 2 1
2 1 1

</pre><hr/><h3>样例输出</h3><pre>1
2
2
3
6
7
-1

</pre><hr/><h3>提示</h3><p><p><span style="font-size: medium">输出解释:</span></p>
<p><span style="font-size: medium">路经分别为(5-1), (5-3-1), (5-2-1), (5-3-2-1), (5-4-3-1),<br />
(5-4-3-2-1).<br />
</span></p></p><hr/><h3>题目来源</h3><p>Gold</p>
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